The just-released Windows 8.1 Update is a worthy attempt to bridge the significant divide between Windows 8's touch-oriented Start screen and Windows Store apps (formerly known as Metro apps) and the more traditional mouse-and-keyboard-oriented desktop and applications.

But while the update does well in bringing those two interfaces closer together, I found that it doesn't go quite all the way in making the operating system feel like a unified whole. And it also lacks an important feature that many desktop users (including me) have been asking for since the launch of Windows 8 -- the Start menu. For that, Microsoft says, people will have to wait an unspecified amount of time for another update.

Metro apps get desktop-friendly

From the moment I first tried out Windows 8, I've felt as if I were running not one operating system, but two. The Start screen and its Metro (sorry, Windows Store) apps work one way and the desktop applications work another, making up two essentially independent worlds. For example, in Windows 8 and 8.1, desktop applications show in the desktop's taskbar when they run, and Metro apps don't. Desktop applications can be closed clicking an X on the upper right, or minimized by clicking a -. Not so for Metro apps. And so on.

With this Windows 8.1 Update, that changes. A new setting lets you change the behavior of Windows Store apps to make them work more like desktop apps. You go to PC settings --> PC and devices --> Corners and edges, and in the "App switching" area, turn on the "Show Windows Store apps on the taskbar" setting. (Note: I reviewed the Windows 8.1 upgrade on a Surface 2 tablet with keyboard and mouse; on at least some, and possibly all, traditional non-touch PCs, this setting is enabled by default.)

A new setting lets you change the behavior of Windows Store apps to make them work more like desktop apps.

From that point on, whenever you run a Windows Store app, it will appear on the taskbar in the same way that desktop applications normally do, making it easy to switch to. You'll also be able to pin Windows Store apps to the taskbar so that you can launch them from the desktop. (Previously, you had to switch to the Start screen in order to launch them.)

In addition, two buttons appear on the upper-right of Windows Store apps when you put your mouse in the upper-right corner: An X for closing the app and a - for minimizing it, just like desktop apps have. In addition, you can now also make the taskbar appear at the bottom of Windows Store apps by moving your mouse to the bottom of the screen. (The taskbar appears at the bottom of all desktop applications.)

Windows Store apps also now have a desktop-application-style title bar that appears briefly when you launch the app and then vanishes, although you can make it appear again by moving your mouse cursor up to the top of the screen.

All this goes a way towards making Windows 8.1 feel more like a unified operating system. I no longer find the process of using first a desktop application and then a Windows Store app as jarring as before, because their behavior is now much more similar.

Having the taskbar available wherever I am is perhaps even more important to me. It means that I am able to easily switch between running apps or launch new apps whether I am in the touch-oriented interface or the mouse-and-keyboard one. In fact, it makes the Start screen less necessary, because you can now launch Windows Store apps from the taskbar.

Having the taskbar available no matter where you are in Windows makes switching between apps a lot easier.

Not everything has been fixed. You still can't resize Windows Store apps, so they can't float on the desktop in their own windows in the way that desktop applications can. And, as mentioned previously, there is still no Start menu, which would further unify the two interfaces. At the recent Build conference, Microsoft showed what the Start menu will eventually look like: very like the one in Windows 7, but also able to display Windows Store app live tiles. When it's released, the unification of the different interfaces will be more complete. But we still have to wait.

More Start screen changes

Microsoft has made some other tweaks to the Start screen as well, and all are useful, although none as significant as the taskbar. There's now a power button on the Start screen, making it a bit easier to shut down Windows 8.1, put it to sleep or restart it. There's also now a search button -- which is actually redundant, because in order to launch a search when you're on the Start screen, you only need to start typing or else display the Search charm. But many people may not know that, and this provides a more obvious alternative. For me, it made no difference at all.

In addition, mouse users will now be on more familiar ground when it comes to customizing the Start screen. It used to be that when you right-clicked a tile, an app bar would appear that let you customize it -- for example, change its size or turn off a live tile. That same bar would appear if you held your finger on the tile using a touch device.

Now when you right-click a tile, a pop-up menu appears with the options, which is more in keeping with what we're used to on the desktop. (If you're using a touch screen, you still get the app bar.) And there are now options for pinning and unpinning the tile from the taskbar.

When you right-click a tile, a pop-up menu appears with the options, which is more in keeping with what we're used to on the desktop.

While this new behavior will please desktop users, I found it confusing when I switched back and forth between using touch and a mouse on the same machine. It shows the inconsistency of having two different interfaces in the same operating system.

Change in default Windows behavior

In the first Windows 8.1 release, Microsoft introduced an option that allowed people to boot straight to the desktop. In this Windows 8.1 Update, booting to the desktop becomes standard for non-touch devices. It's a much bigger change than you might first think, because it means that when people buy new systems, they'll boot into the interface best suited for the computer they're using -- the desktop for non-touch machines and the Start screen for touch machines.

If you already have Windows 8.1 on a system and you load the Windows 8.1 Update, Windows will follow whatever behavior you've already set for it. So, for example, if you have a non-touch PC, but you've set it to boot to the Start screen, you'll still boot to the Start screen unless you decide to change Windows' behavior.

Other additions and changes

There are plenty of other additions and changes. When you install a new Windows Store app now, you get a notification on the Start screen next to a down arrow. Click or tap the arrow and you're sent to a screen that shows all of the apps on your PC, with any new ones highlighted. The notification and highlight stay there until you launch the app for the first time.

There are also a number of changes to PC settings. Microsoft has finally added a Control Panel link to the bottom of the main settings screen, something that had been bafflingly overlooked until now. In the PC and Devices settings area, a new disk space screen displays how much space is being taken up by apps and files, and lets you delete apps if you think they're taking up too much space.

The update also fixes something that has annoyed me ever since Windows 8 launched: that when you double-clicked a graphics file such as a JPG using File Explorer, it always opened the file in the Windows Store Photos app, which I find far less useful than the desktop photo application (Windows Photo Viewer). Now Windows is more intelligent about that: Open a graphics file from the desktop using File Explorer and it opens the file in the desktop application. Open the same file from a Windows Store app, and it launches the Windows Store Photos app.

The bottom line

This update has gone a long way toward making Windows 8.1 appear to be a single operating system rather than two OSes bolted uncomfortably together, notably by having Windows Store apps behave more like desktop apps and having the taskbar available on both the Start screen and desktop. And having Windows automatically boot to the desktop on new, non-touch PCs is a big step forward as well.

Still, I don't think Microsoft has quite nailed it yet. Windows Store apps still look and work differently than desktop apps -- they tend to be more graphically oriented and have far fewer features, just what you would expect in a touch-oriented tablet apps. They still can't be resized or run in separate windows on the desktop. And there's still no Start menu.

If those two issues were fixed, Windows 8.1 might finally seem like a single operating system that can shape-change according to whatever device you're using, rather than two different operating systems coexisting on the same machine.